Apparatus for drilling dowel-holes and the like



E. MURSCHEL Jan. 25, 1966 APPARATUS FOR DRILLING DOWEL-HOLES AND THE LIKE '7 Sheets-Sheet 1 Filed April 26, 1965 fiwi 71 I11 urschel BY lflz'chdel S. Striker' ATTORNEY Jan. 25, 1966 E. MURSCHEL 3,230,797

APPARATUS FOR DRILLING DOWEL-HOLES AND THE LIKE Filed April 26, 1963 '7 Sheets-Sheet 2 INVENTOR ZZIurschel Y [Hie/me! S. Striker ATTORNEY Jan. 25, 1966 K E. MURSCHEL 3,230,797

APPARATUS FOR DRILLING DOWEL-HOLES AND THE LIKE Filed April 26, 1965 '7 Sheets-Sheet 3 Fig. 3

INVENTOR i wi n HZursc/ze/ BY ZYZicizdg/ s. Striker ATTORNEY E. MURSCHEL 3,230,797

APPARATUS FOR DRILLING DOWEL-HOLES AND THE LIKE Jan. 25, 1966 7 Sheets-Sheet 4 Filed April 26, 1963 INVENTOR [ll uYsc/ze/ BY YYIic/mlel Sir-7K0) ATTORNEY E. MURSCHEL 3,230,797

APPARATUS FOR DRILLING DOWEL-HOLES AND THE LIKE Jan. 25, 1966 7 Sheets-Sheet 5 Filed April 26, 1963 EN w INVENTOR I? 7 u make! 7 win A'ITORNEY Jan. 25, 1966 APPARATUS Filed April 26, 1963 E. MURSCHEL 3,230,797

FOR DRILLING DOWEL-HOLES AND THE LIKE '7 Sheets-Sheet 6 285 d/Am INVENTOR Erwin I22 ursche/ ATTORNEY Jan. 25, 1966 E. MURSCHEL APPARATUS FOR DRILLING DOWEL-HOLES AND THE LIKE 7 Sheets-Sheet '7 Filed April 26, 1963 INVENTOR frwin 7)]u 719046/ BY /7?ichde/ 5. ir K67 I ATTORNEY United States Patent APPARATUS FOR DRILLING DUWElL-HGLES AND THE LIKE Erwin Murschel, Stuttgart-Weilimdorf, Germany, assignor to C. F. Scheer & Cie, Stuttgart-Feuerbach, Germany Filed Apr. 26, 1963, Ser. No. 275,886

Claims priority, application Germany, Apr. 28, 1962,

Sch 31,385 27 Claims. (Cl. 77--5) The present invention relates to apparatus for drilling blind bores (such as dowel-holes) or through bores in panel-like workpieces which may consist of wood, metal or plastic. More particularly, the invention relates to an apparatus which is especially suited for drilling patterns of holes or bores in large panels, plates, sheets and similar bulky workpieces It is an important object of the invention to provide an apparatus which is constructed and assembled in such a way that patterns or designs comprising large numbers of blind bores or through bores may be drilled consecutively and with utmost precision, particularly in mass manufacturing of parts which are to be assembled by means of dowels, and it is also an object of the invention to construct the apparatus in such a way that a bulky workpiece need not be shifted, turned or otherwise displaced once it is mounted in the apparatus even though the distribution of holes or bores might be such that the bores or holes are spread over large areas of the workpiece and even if some or all of the holes must be drilled in the end faces of the workpiece.

Another object of the invention is to provide an apparatus of the just outlined characteristics which is assembled in such a way that it may be converted with minimal delay from drilling of holes in the front side to drilling of holes in an end face of a panel-shaped workpiece or vice versa, and which may be manipulated by semiskilled persons without much danger that a less skilled operator would be incapable of properly controlling and carrying out the drilling operation.

A further object of the instant invention is to provide an apparatus for drilling dowel-holes or the like wherein larger or smaller workpieces may be handled with equal precision, which may be utilized for simultaneous drilling of two or more holes, which is capable of properly locating both sides and all end faces of a workpiece, and which may be utilized for alternatively drilling deeper or comparatively shallow dowel-holes.

An additional object of my invention is to provide an apparatus of the above outlined characteristics wherein a workpiece may be located and fixed in requisite position with little loss in time so that the output of the apparatus exceeds substantially the output of all such conventional apparatus of which I have knowledge at this time.

Still another object of the invention is to provide an apparatus for making dowel-holes in wooden panels and the like wherein the drilling unit or units are mounted in such a way that the tool or tools need not be detached therefrom at the time the units are moved to different positions of adjustment with respect to the workpiece.

A concomitant object of the invention is to provide an apparatus wherein a single drilling tool may reach all sections of a workpiece regardless of the dimensions of the workpiece so that the latter need not be detached and its position altered in order to form dowel-holes or through bores in all or nearly all sections thereof.

A further object of the invention is to provide an apparatus of the above outlined characteristics which may be used for drilling mirror symmetrical patterns of holes or bores in consecutive workpieces and which may be "ice used for drilling of such patterns with utmost precision so that a set of dowels may be fitted into such holes or bores with maximum accuracy.

An additional object of my invention is to provide an apparatus which is constructed and whose work-supporting parts are assembled and positioned in such a way that an operator of normal stature can reach all parts of the apparatus without being compelled to cover considerable distances while servicing the apparatus in actual use.

. A further object of the invention is to provide a novel system of locking or arresting devices for the drilling unit or units of my improved apparatus and to construct such arresting devices in a manner to insure that each arresting device may be readily adjusted for a different operation and that each arresting device may be readily detached from and reconnected to the frame or to another part of the apparatus.

Another object of the invention is to provide an apparatus of the above outlined characteristics which enables an operator to move the drilling tool to different positions with respect to the workpiece in such a way that precise adjustments of the tool in new positions may be completed with little loss in time and that the intervals of time necessary for such adjustments constitute but a small fraction of the time during which the apparatus performs useful work.

Another object of my invention is to provide a novel retaining device which is capable of properly holding relatively long, short, thick and/or thin workpieces, and which can simultaneously serve as a means for changing the distance between the workpiece and the drilling unit or the inclination of the workpiece if the operator desires to change the depth or the inclination of dowelholes.

A further object of the invention is to provide an apparatus for drilling dowel-holes or through bores in which the position of the workpiece or of the drilling units may be adjusted in the intervals between the formation of consecutive dowel-holes so that a workpiece may be provided with sets of deeper and shallower holes in a continuous operation and in a time-saving manner.

With the above objects in view, one feature of the invention resides in the provision of an apparatus for drilling blind bores or through bores in panels and similar workpieces, particularly in front sides and in two oppositely located end faces of rectangular panels. The apparatus comprises a work supporting frame including a series of preferably rectangularly arranged frame members which define between themselves a drilling area in which the actual drilling or milling operation takes place, a retaining device which may be operated by pressure fluid and whose parts are arranged to fix a workpiece in the frame so that at least a portion of the workpiece is accommodated in the drilling area and that one side and preferably one or more end faces of the workpiece remain fully or nearly fully exposed, a tool support mounted on the frame and arranged to reciprocate in the direction of one dimension of the drilling area, and

at least one drilling or tool supporting unit provided on and reciprocable with respect to the tool support in the direction of the other dimension of the drilling area. To that end, the tool support preferably comprises a tool holder which spans the drilling area in a direction normally parallel with the other dimension of the drilling area, and this tool holder serves as a rail or guide for the drilling unit so that a milling or drilling tool which is mounted in the unit may reach all or nearly all sections of the drilling area and may be readily located in any position within the range of the tool support in response to reciprocation of the tool support with respect to the frame and/ or in response to reciprocation of the drilling unit with respect to the tool support. This is a decided advantage when drilling heavy parts which could not be shifted easily.

In accordance with another feature of my invention, the drilling area is preferably located in a vertical or nearly vertical plane and, if it is necessary to drill-dowelholes in the one or in the other lateral (vertical) end face of the workpiece, I may mount the entire tool support or the tool holder in such a way that it may rotate about a vertical axis in order to move the drilling tool into a position at right angles or into a position at another angle with respect to the plane of the one or the other end face of the workpiece.

In certain conventional apparatus for drilling dowelholes in panels and similar bulky workpieces, the tool support is stationary and the retaining means for the workpiece moves with respect to the frame in order to move selected sections of the workpiece into the range of the tool. I have found that my apparatus wherein the workpiece remains stationary and wherein the tool moves to different positions relative to the workpiece presents a number of important advantages, such as easier handling because the weight of the tool support is normally less than the combined weight of the workpiece and of the retaining means therefor, and also because the apparatus can form holes or bores with greater accuracy and at greater speed, i.e., the intervals between the consecutive drilling operations are reduced to a minimum.

The component .parts of the retaining means in my improved apparatus are preferably arranged in such a way that they may engage a workpiece at both longitudinal ends, and the mounting of the tool support is preferably such that the support may move the tool anywhere at least within that area which extends between the component parts of the retaining means. However, and particularly when the apparatus is used for drilling holes in the front side and in one or more end faces of a workpiece, the tool support or a portion thereof may move beyond the retaining means so that it may locate the tool against a selected end face of the workpiece.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved apparatus itself, however, both as to its construction and its method of operation, together with additional features and advantages thereof, will be best understood from the following detailed description of certain specific embodiments with reference to the accompanying drawings, in which:

FIG. 1 is a front elevation view of an apparatus which embodies one form of my invention;

7 FIG. 2 is an enlarged vertical section as seen in the direction of arrows from the line, 2'-2 of FIG. 1;

'FIG. 3 is an enlarged vertical section as seen in the direction of arrows from the line 3-3 of FIG. 1;

FIG. 4 is an enlarged fragmentary detail view of a portion of the structure shown in FIG. 2;

FIG. 5 is an enlarged fragmentary front elevational view of two spaced portions of the apparatus which are shown encircled by dot-dash lines in FIG. 1;

FIG. 6 is an enlarged fragmentary end elevational view of the apparatus as seen-in the direction of arrow A in FIG. 1;

FIG. 7 is a front elevational view of a modified apparatus;

I FIG. 8 is an enlarged vertical sectionas seen in the direction of arrows from the line 8-8 of FIG. 7; and

FIG. 9 is an enlarged fragmentary detail view of the modified apparatus as seen in the direction of arrow B in FIG. 7, the drilling unit being shown in a different position in which the drilling tool may form holes in the end face of a flat panel-like workpiece.

Referring now in greater detail to the drawings, and first to FIGS. 1 to 3, there is shown an apparatus which is especially suited for making dowel-holes in wooden panels and similar workpieces. The apparatus comprises a composite frame including a horizontally extending elongated lower frame member 14 which is mounted on two supporting legs 10, 12, a horizontal upper frame member 16 which is parallel with the lower frame member, and two spaced vertically extending lateral frame members 18, 20. These frame members define between themselves a rectangular drilling area DA one dimension of which (i.e., its length) is parallel with the frame members 14, 16 and the other dimension of which (i.e., its width or height) is parallel with the frame members 18, 26. The frame supports a specially constructed tool support 22 which spans one dimension (i.e., the width or height) of an area DA and which is reoiprocable relative to the frame in a direction which is parallel with the other dimension (i.e., with the length) of this area. The apparatus comprises arresting means (to be described later) for releasably fixing the tool support 22 in a number of selected positions of adjustment relative to the horizontal frame members 14, 16.

The lower frame member 14 comprises a U-shaped beam 24 Whose lower flange 26 is welded or otherwise secured to the legs 10, 12, see FIGS. 2 ancl 3. The web 24a of the beam 24 is disposed in a vertical plane and provides a rigid connection between the flange 26 and an upper flange 28. This web supports at its rear side (i.e., at that side which faces away from the tool support 22) a pair of elongated L-shaped rails 30, 32 which are mirror symmert'ical to each other with reference to a horizontal plane. The underside of the rail 32 rests on the legs iii, 12 and is coplanar with the underside of the flange 26. The upper side of the other rail 34} is coplanar with the upper side of the upper flange 28.

The lateral frame members 18, 2t) assume the form of U-beams and the lower end portion of the frame member 18 is welded or otherwise fixed to the rails 39, 32 so that the frame members 14, lti'form a rigid L-shaped unit. However, the lower end portion of the frame member 20 is detachably secured to the rails 3t 32 by a clamping device 34 best shown in FIG. 3. This clamping device comprises a T-shaped clamping element 36 which is 'slidably received between the rails 30, 32 and which carries a threaded spindle 37 extending through an opening 20a provided in the Web 2015 of the frame member 20. The spindle'37 mates with a clamping nut 4% which is provided with a handle 38 and whose diameter is such that it may abut against the flanges 20c, 20d of the frame member 2%) (see FIG. 1) in order to force the clamping element 36 into strong frictional engagement with the rails 30, 32.

The apparatus further comprises a composite retaining device whichserves to detachably fix a workpiece 66 to the frame in such a way that at least a portion of the workpiece is located within the area DA. This retaining device comprises a first fixture 43 which is mounted on the frame member 18 and a second fixture 43 which is mounted on the frame member 20,-see particularly FIGS. 2 and 3. Since the two fixtures are of identical design, it is suflicient to describe only that fixture which is carried by the adjustable frame member 26. This fixture comprises a fluid-operated cylinder and piston assembly which is mounted substantially midway between the ends of the frame member 2% and which faces in a direction away from the tool support 22. The cylinder 44 of this assembly is secured to the web 20b by means of bolts or screws 46 and accommodates a piston 45 whose rod 43 extends r-earwardly of the apparatus and is rigidly fixed to a vertical platen 50 whose ends are connected with horizontal tie rods 52, 54-. These tie rods extend through openings 53 provided in the web 20b and have their forward ends secured to a second vertical platen 56 which is adjacent to the front side of the Workpiece 66. The cylinder 44 is connected with two conduits 62, 64 which alternately admit pressure fluid (preferably oil) at the opposite sides of the piston 45 so that the piston rod 48 may compel the platen 5t to'move in a di= r'ection to the right, as viewed in FIG. 3, and to force the platen 56 into strong engagement with the workpiece 66 whereby the rear side of the workpiece bears against a plate-like insert or back support 58 which is placed in front of the frame member 20 so as to abut against the web 20b. The back support 58 rests on a bottom support or block 60 which issecured to the lower portion of the web 20b (just above the lower frame member 14) by screws or the like, not shown. The block 60 also serves as a rest for the lower end face of the workpiece 66. A similar second block 60 is fixed to the lower portion of the frame member 18.

An important advantage of the feature that the frame member 20 is movable toward and away from the frame member 18 is that the two fixtures 43 may engage the workpiece 66 at or close to its longitudinal ends. and if the workpiece 66 of FIG. 1 is replaced by a shorter workpiece, the operator merely releases the clamping device 34 and a similar clamping device 68, whereupon the frame member 20 may be shifted in parallelism with itself so as to move toward the frame member 18. The clamping device 68 is similar to the device 34 and serves to provide a readily releasable connection between the upper end portion of the frame member 20 and the upper horizontal frame member 16. This clamping device 68 comprises a nut 72 which is provided with a handle 69 and which mates with a spindle 73, the latter extending through an elongated horizontal slot 74 which is provided in the frame member 16 and through an opening provided in the web 20b. The rear end of the spindle 73 is provided with a head 75 which abuts against the rear side of the web 20b so that, when the handle 69 is caused to rotate the nut 72 in a given direction, the frame members 16, 20 are securely clamped to each other. The left-hand end portion of the upper frame member 16 (as viewed in FIG. 1) is preferably rigidly secured to the upper portion of the frame member 18 so that the frame members 14, 16, 18 together form a U-shaped assembly.

The tool support 22 comprises a lower portion 76 which assumes the form of a carriage and which is reciprocable along the front side and in the longitudinal direction of the lower horizontal frame member 14. The carriage 76 is controlled in its reciprocatory movements by an elongated guide rail 78 which is secured to the front side of the web 24a by spaced brackets 80, 82, and the movements of the carriage are further controlled by the lower flange 26 of the beam 24. The brackets 80, 82 are located at the longitudinal ends of the web 24a. As shown in FIGS. 1 to 3, the carriage 76 supports two rearwardly extending shafts each of which carries a first roller or wheel 84, 86 and a second roller or wheel 88, 90. The rollers 84, 86 are rotatable about horizontal axes and travel along the upper end face of the guide rail 78; the axes of the rollers 88, 90 are vertical and these rollers travel along the rear side of the rail 78. Two additional rollers 92, 94 which are supported by the carriage '76 in such a way as to be rotatable about vertical axes track the front end face of the flange 26. It will be noted that the system of rollers 84, 86, 88, 90, 92, 94 enables the carriage to move with little friction along the combined guide means which includes the rail 78 and the flange 26.

The carriage 76 is rigid with an upwardly extending vertical tool holder 96 which spans the area DA and whose upper end portion is releasably secured to the frame member 16 by a clamping device 100. In the illustrated embodiment, the tool holder 96 is parallel with the lateral frame members 18, 21). The clamping device 160 comprises a horizontal spindle 99 which extends through a spacer sleeve 98 fixed to the upper end portion of the tool holder 96 and arranged to abut against the front side of the frame member 16. The spindle 99 extends through the slot 74 and meshes with a nut 101 which is provided at the rear side of the frame member 16. The means for rotating the spindle 99 comprises a handle 103 which is located at the front side of the tool Thus,v

d holder 96. It goes without saying that the slot 74 may be extended all the way to the frame member 18 so that the tool support 22 may be reciprocated across the entire drilling area DA.

As best shown in FIG. 3, the tool holder 96 assumes the form of a U-shaped channel bar which is open toward the lateral frame member 20 and which carries at its front side a vertically extending guide rod 102 serving as a means for controlling movements of a drilling or tool supporting unit 104 having a rotary and axially reciprocable drilling tool 126 whose axis is normally perpendicular to the plane of the front side of the workpiece 66. The exact construction of this drilling unit forms no part of my invention. As shown in FIG. 1, the housing of the unit 1134 is provided with a stirrup-shaped handle 196 which may be grasped by hand in order to shift the unit along the guide rod 102. The handle 1116 supports one component part of an arresting or locking device which serves to hold the drilling unit 104 in a selected position of vertical adjustment with respect to the tool holder 96. This component part constitutes a locking member and assumes the form of a horizontal stud or belt 119 which includes a knurled portion serving as a handgrip means and which is permanently biased by a spring 108 in a direction to move its inner end portion toward the left-hand side of the holder 96, reference being had to FIG. 1. The inner end portion of the stud 116 is formed with a conical blind bore 109 which may receive one of several projections 114 provided on a removable second component 112 of the arresting device. The second component 112 assumes the form of an elongated rail or strip which is detachably fixed to the exposed side of the web of the U-shaped tool holder 96 by means of screws or the like and which is provided with a longitudinally extending channel 113 for a series of locating projections 114. Each projection 114 comprises a conical tip 114a which may be received in the recess 169 of the stud and a rear portion which is slidable in the channel 113 and which may be securely fixed in a selected position of adjustment with respect to the strip 112. Thus, if the operator desires to move the drilling unit 194 to a different level, he must pull the stud 111 against the bias of the spring 198 so as to move the bore 109 away from the tip of the cooperating projection 114, whereupon the unit 104 is free to slide along the guide rod 102 until the stud 110 moves into registry with the tip 114a of a new projection 114. It goes without saying that the arresting device may be modified by forming the strip 112 with recesses or bores and by providing the tip of the stud 11% with a projection which may be received in a selected recess or bore of the strip. This would merely amount to a reversal of the construction but would be an obvious equivalent of the arresting device which is shown in the drawings.

The upper end portion of the tool holder 96 supports a pulley 115 which is rotatable about a horizontal axis. A flexible element 116 which is trained around the pulley 115 is fixed to the drilling unit 104 at one end and to a counterweight 118 at the other end so that the counterweight prevents uncontrolled movements of the drilling unit when the stud 114) does not engage a projection 114. The counterweight 118 is accommodated in the space defined by the U-shaped holder 96, see particularly FIG. 3.

The apparatus of my invention further comprises a second arresting or locking device whose construction is similar to the construction of the arresting device 110, 112. This second arresting device comprises an elongated strip or rail 129 (see also FIGS. 4 to 6) whose front side is formed with a T-shaped channel 121 for a series of longitudinally adjustable locating projections 124. The strip 121) is detachably fixed to the upper side of the flange 28 and is located in front of the blocks 66. The projections 124 may cooperate with a locking memher here shown as a horizontally reciprocable stud 122 which is mounted in the carriage '76 and which is biased by a'suitable spring (not shown) similar to the spring 108 forthe stud 114 so that its blind bore 122a (see FIG. 4) normally receives the conical tip 124142 of a selected projection 124. The projections 124 are formed with threaded bores which receive the stems of short bolts 132, and the heads of these bolts are non-rotatably received in the channel 121 so that they cannot be turned with respect to but that they are slidable in the longitudinal direction of the strip 128. Each projection 124 comprises a non-circular portion 12% (see particularly FIG. 6) which is adjacent to the respective tip 124a and which may be engaged by a suitable wrench or another tool in order to drive the respective screw bolt 132 home and to lock the projection to the strip 120.

The arresting device 120, 122 enables an operator to fix the drilling unit 1% in any selected position of adjustment longitudinally of the workpiece 66 so that the drilling tool 126 may be moved to a selected section of the drilling area DA. In the embodiment of FIGS. 1 to 3, the drilling tool 126 may be moved within a space whose length is determined by the length of the slot '74 and whose height is determined by the length of the guide rod 102. As stated herein-above, the slot 74 may be extended all the way to the frame member 18, and it is equally possible to extend the rod 1 02 all the way to the upper frame member 16.

The means for detachably securing the strip 12% to the frame member 14 comprises a pair of claws or straps 128 which are provided at the ends of this strip and which are secured to the rail 30 by winged bolts 13%, see FIG. 4. Of course, it is equally possible to provide a detachable connection between the upper flange 28 and the straps 128. The construction of the arresting device 120, 122 may be modified by forming the stud 122 with a projection which may be received in one of a series of recesses or bores provided in the front side of the strip 12%. However, the construction of FIGS. 1 to 6 is normally preferred because it allows for rapid adjustment of the projections 124 so that the apparatus may be converted for drilling of dowel-holes or the like in different types of workpieces and for drilling such holes at different distances from each other.

In order to positively prevent any longitudinal displacements of the workpiece 66 when the apparatus is in actual use, I prefer to provide a pair of so-called end stops at least one of which is normally maintained in operative position when the workpiece rests on the blocks 60 and is held in position by the fixtures 43 of the composite retaining device. In addition, such end stops hold the workpiece against longitudinal movement at the time the fixtures 43 are applied, i.e., at the time the piston rods 48 are caused to move in a direction to the right, as viewed in FIG. 3, in order to force the platens 56 into engagement with the front side of the workpiece. Each such end stop comprises a turnable and/or vertically reciprocable lever 134 which is fixed to the lateral side of the respective block 60 by a screw bolt 136 and which is formed with an elongated slot 135 so that, when the respective bolt 136 is loose, the lever may be caused to descend beneath the lower end face of the workpiece, see the right-hand portion of FIG. 5. ltpwill be readily understood that the slots 135 may be replaced by circular holes and that the levers 134 may be simply rotated about the stems of their respective bolts 136. All that counts is to provide a pair of end stops which may be rapidly moved into or out of engagement with the adjacent lateral end faces of the workpiece 66 so that the workpiece is held against longitudinal displacement in at least one direction.

In accordance with another feature of my invention, the apparatus is provided with setting means which enables an operator to drill two groups of dowel-holes which are arranged in mirror symmetry with reference toeach other. For example, the operator may have to drill a pattern of holes in the left-hand section of the workpiece 66, as viewed in FIG. 1, and to thereupon drill a similar pattern of holes in the right-hand section of the workpiece. The two patterns should be mirror symmetrical to each other with reference to a vertical plane which is perpendicular to the plane of FIG. '1 and which passes midway between the ends ofithe workpiece. Such setting means also enables anoperator to form a mirror symmetrical pattern of holes in another workpiece which is being drilled in a subsequentoperation. The construction and operation of the setting means will now be described with reference to FIG. 5.

As shown in-the left-hand portion of FIG. 5, the lefthand lever 1'34 engages the adjacent lateral end face of the workpiece 66. The distance between the-center of the leftmost projection 124 and the left-hand end face of the workpiece '66 is indicated at a. The strip 120 is held in the illustrated position by an adjusting element 138 which is fixed to its left-hand-end and which extends along and abuts against the left-hand side face of the block 6%) '(see also FIG. 6). A screw 140 which is carried by the block extends through an open slot 142 of the adjusting element 138 and, since the element 138 abuts against the block 60, the strip is fixed in position so that the distance between the leftmost projection 124 and the left-hand lateral end face of the workpiece 66 remains unchanged. If the operator then desires to drill a similar pattern of holes in the right-hand portion of the next workpiece,the strip 120 is removed from the frame upon turning of thewinged bolts and is inverted through degrees so that the projection 124 which was previously adjacent to the left-hand lever 134 (see the left-hand portion of FIG. 5) is now adjacent to the right-hand lever 134- as indicated by phantorn lines at 124 in the right-hand portion of FIG. 5. The next workpieceis placed onto the blocks 60 and the right-hand lever 134 is moved upwardly to engage the right-hand lateral end-face of the workpiece. The operator then turns the right-hand screw 14%} to move the adjusting element 138 into abutment with the right-hand end face of the right-hand'block 60 which'insures that the projection 124 (in the position 124') 'is located at a distance a from the right-hand lateral end'face of the new workpiece.

The just described setting means insures that the apparatus will form patterns of mirror symmetrical holes with utmost precision. Such precision is very difiicult to attain if the projections 124 are caused to change their positions subsequent toforming a given pattern of holes in a first workpiece.

When the strip 112 or 120 is detached from the frame preparatory to making a-new setup fora different operation, the position of the projections .114, 124 may be adjusted with the help of suitable templates which insure that the projections are positioned with utmostaccuracy. Alternatively, the apparatus may be furnished with sev eral sets of strips 112, 120 each of which may be used in drilling a given pattern of bores or holes. Iu'such instances, the projections 114, 124 may be permanently secured to the 'respectivestrips. It will be readily understood that the intervals between consecutive operations with differently arranged projections will be reduced considerably if the apparatus is furnished with several sets of strips 112, 120 because no time need be lost for resetting the projections in order to drill a different pattern of holes with the help of a single strip 112 or 120. Nevertheless, it'was found that a single set of such strips normally sufiices if the projections are adjustable.

Of course, it is not absolutely necessary to separate the strips 112, 120 fromthe frame when the projections 114, 124 must be moved to new positions. As described hereinabove, such adjustments may be made'while the strips remain fixed to the frame and to the tool-holder.

In certain smaller apparatus, the tool support 22 may be guided with requisite accuracy evenif'the clamping device 100 at the upper end of the tool holder 96 is dispensed with. Furthermore, if this clamping device is omitted, the carriage 76 may move all the way to the frame member 18 despite the fact that the slot 74 need not extend along the full length of the frame member 16. However, and particularly in heavy-duty constructions, the apparatus should normally comprise some means for guiding the tool support along two spaced frame members at the opposite sides of the drilling unit. The tool holder 96 is normally strong enough to support two or more drilling units, two or more milling units or a combination of drilling and milling units. When the tool support 22 is guided solely by the frame member 14, the upper frame member 16 may be omitted because the apparatus may be readily modified in a sense to guide the adjustable frame member 20 only along the rails 30, 32, i.e., that the guide slot 74 and the clamping device 68 are no longer necessary.

Owing to the fact that the frame member 22 is adjustable in directions toward and away from the frame member 18, the apparatus of my invention may be equipped with a lightweight frame which need not include a bulky work-supporting table such as is used in many types of conventional apparatus and which provides a full-sized back rest for smaller or larger workpieces. Such tables add to the cost and particularly to the overall weight of the machine. Moreover, and as explained hereinabove, it is always of advantage to retain the workpiece close to its ends in a manner as shown in FIG. 1 wherein the distance between the fixtures 43 may be varied by moving the frame member 20 in the longitudinal direction of the area DA.

The distance between the front side of the workpiece 66 and the tool support 22 may be varied by furnishing the apparatus with sets of back supports 5% of different thicknesses. Thus, the operator may control the depth of dowel-holes 66a (see FIG. 2) without being corn pelled to replace the tool 126 by a shorter or a longer tool. By using two back supports 58 of different thicknesses, the operator may fix the workpiece in a position in which the front side of the workpiece is not perpendicular to the axis of the tool 126. This may become necessary in the event that the dowel-holes must be drilled at an angle other than 90 degrees.

When the motor of the drilling unit 104 is started, the tool 126 rotates and is simultaneously caused to penetrate into the front side of the workpiece 66 to drill a hole of desired depth.

FIGS. 7 and 8 illustrate a modified apparatus which again comprises a substantially rectangular frame including a lower framemember 214 whose main component assumes the form of an elongated U-shaped beam 224 having a lower flange 227 which is welded to the legs 210, 212. The rear side of the web 224a carries a pair of L-shaped rails 230, 232 which are secured to the beam 224 in the same way as described in connection with FIGS. 1 to 3. The ends of the beam 224 are connected with two vertically upwardly extending lateral frame members 218, 220, and the upper ends of these frame members are rigidly connected with the ends of a horizontally extending upper frame member 217. The frame member 217 is of inverted U-shaped cross section and defines an elongated channel whose purpose will be described hereinafter. The parts 214, 217, 218, 225] together form a rigid rectangular frame defining a drilling area DA which is located in a vertical plane and whose horizontal dimension (length) exceeds its vertical dimension. At the front side of this rigid frame, there is provided a reciprocable tool support 222 which may be held in selected positions of adjustment by an arresting or locking device including a horizontally extending strip or rail 320 for a series of projections 324, and a locking member in the form of a horizontally reciprocable bolt or stud 322. The construction of this arresting device is analogous to that of the device 120, 122 which was described in connection with FIGS. 1 to 6, and its purpose is to hold the tool support 222 against longitudinal displacement with respect to the horizontal frame members 214, 217 at the time the drilling unit 304 is in actual use or at the time the operator desires to adjust the drilling unit 304 in a vertical direction. The strip 320 is secure-d to the rail 230 or to the upper flange 229 of the beam 224. The driving connection between the motor of the unit 304 and the drilling tool .326 is of known design and forms no part of this invention. The motor may receive current through a flexible conductor or through a live rail.

The drilling unit 364 is mounted on a slide 306 which is arranged to move between a pair of spaced vertical legs 245, 247. These legs together form part of a tool holder which corresponds to the tool holder 96 of FIG. 1. The leg 245 carries a strip or rail 312 whose function is the same as that of the strip 112 and which is provided with longitudinally adjustable projections 314. Any one of these projections 314 may be received in a conical bore provided at the inner end of a locking member here shown as a stud or bolt 310a which is mounted in a handle 310 on the slide 306. The handle 310 is rotatable about a vertical axis and the bore of the bolt 310a may receive or moves away from a selected projection 314 in response to such rotation of the handle.

In contrast to the mounting of the drilling unitltld, the unit 304 is not only reciprocable along the legs 245, 245 but is also arranged to swivel or pivot with the tool holder about a vertical axis so that it may move the drilling tool 326 against the one or the other lateral end face of the workpiece 266. The mounting of the tool holder is best shown in FIG. 8. Thus, the lower end of this tool holder comprises a vertical pivot 353 which is rotatably received in a vertical bearing sleeve 351 forming part of a carriage 255. This carriage is reciprocable along the lower frame member 214. The rear side of the sleeve 351 carries a shaft for a pair of rollers or wheels 234, 288 the former of which is arranged to rotate about a horizontal axis and tracks the upper end face of a guide rail 278 which is fixed to the web 224a by a pair of spaced brackets 281), 282. The other roller 288 travels along the rear side of the rail 27% and rotates about a vertical axis. The upper end portion of the sleeve 351 is provided with an annular flange 257 which serves to support the underside of a boss 353a, this boss being rigid or integral with the pivot 353 and serving to prevent axial displacements of the pivot in downward direction. A locking pin or bolt 267 extends through the flange 257 and may be received in one of a series of openings 269 (see FIG. 9) provided in the underside of the boss 353a to hold the legs 245, 247 against rotation about the axis of the sleeve 351. Thus, whenever the operator desires to change the angular position of the tool holder (including the pivot 353) he must withdraw the pin 267 in downward direction in order to release the boss 353a and to permit rotation of this boss relative to the flange 257. The boss 353a forms part of a hollow casting 259 which is rigid or integral with the lower ends of the legs 245, 247 and which constitutes a component part of the tool holder.

The aforementioned stud 322 is reciprocable in a horizontal bore of the casting 259 and its knurled front end portion extends through an aligned aperture provided in a cover plate 2'73 which normally closes the front side of a compartment defined by the casting 259. This compartrnent accommodates a helical spring 398 which bears against the rear side of the cover plate 273 and against a washer 277 on the stud 322 so that the latters rear end port-ion or tip is permanently biased in a direction toward the strip 320 and into engagement with a given projection 324.

The upper ends of the legs 245, 247 are rigid with a connecting member 272 which serves to guide the tool support 222 along the upper frame member 217 and to permit pivotal movements of the tool holder. This con- 'necting member comprises a rearwardly extending lug 280 for a vertical pivot pin 283 whose axis coincides with the axis of the pivot 353. The pin 2% passes through a follower arm 285 which is rigid with a slider 287, and this slider is provided with antifriction bearings so as to travel with minimal friction in the aforementioned channel at the underside of the upper frame member 217. The connecting member 279 further supports a pulley 315 for a flexible element 316 which is connected to the drilling unit .304 at one of its ends and whose other end is connected with a counterweight, not shown, to insure that the drilling unit may be shifted with minimal effort and that this unitwill remain in a given position even if the arresting device 310a, 312 is idle.

The apparatus of FIGS. 7 to 9 further comprises an additional vertical frame member 221 which extends all the way'between the frame members 214, 217 and which is adjustable in the longitudinal direction of the frame. The lower portion of this auxiliary vertical frame member 221 is rigid with a T-shaped clamping element 236 which .is received between the rails 23%, 232 and which forms part of a clamping device 234 serving as a means for releasably fixing the frame member 221 to the frame member 214, i.e., to the beam 224. The construction of this clamping device is analogous to that of the device 34, i.e., it comprises a spindle which meshes with the clamping element 236 and which extends through an opening in the web of the U-shaped frame member 221. The rear end of this spindle carries a head and a handle238 by means of which the spindle may be rotated to move its head against the flanges of the frame member 221 whereby the latter is securely locked to the beam 224. The frame member 221 may be releasably secured to a second auxiliary frame member 216 which extends in a horizontal direction and whose ends are fixed to the frame members 218, 220. This second auxiliary frame member is formed with an elongated slot 274 for the spindle 262 of a second clamping device 2% whose construction is plainly shown in FIG. 8. Thus, before the operator can move the frame member 221 in the longitudinal direction of the frame, he must release the clamping devices 2%, 234 in order to enable the spindle 202 to move in the slot .274 and to enable the clamping element 236 to travel along the rails 230, 232.

The lower portions of the frame members 218, 220 are provided with bottom supports or blocks 26% which serve as abutments for the lower end face of the workpiece 266. The rear side of the workpiece abuts against two spaced vertical back supports 258 whose position is adjustable by pairwise arranged adjusting devices 2%. Two such adjusting devices are provided on each of the frame members 218, 221. The purpose of these adjusting devices is to insure that the workpiece 256 may be located in a plane which is perpendicular to the axis of the tool 326 or that the workpiece may be held in a different position, for example, if the holes to be drill-ed into the front side of the workpiece should not be perpendicular to the plane of the workpiece. The construction of the adjusting devices 2% may be readily ascertained by looking at FIG. '8. In addition, the adjusting devices 296 enable an operator to move the workpiece nearer to or further away from the tool support 222.

The reference surfaces 258a of the back supports 258 determine the position of the workpiece 266. Since the workpieces are often made of wood and may have irregular and partly non-uniform shapes and especially thicknesseses, it is important to be able to change the position of the back supports including their reference surfaces 258aand thus of the workpieces relative to the tool supporting unit in order to insure that the holes to be drilled into the workpiece are in the desired direction and on the desired location, usually at right angles to the surfaces and central or off center to the side edges, which is of special importance when the tool holder is swung into different working positions. In order to achieve the proper location of'the workpiece, it is often required to adjust the adjusting devices 299 separately andthus ,move the reference surfaces 253w of the back supports 25% into the respective orientation which may differ fromthe -vertica1 direction relative to the direction of drilling motion of the tool. As thisadjustment quite often requires very small adjusting motions, the adjusting devices are preferably adapted for fine adjustment, which may be achieved by using elements having fine threads as employed in micrometers. This fine adjustment is greatly facilitated by employing an indicating device which may, asin the present embodiment, comprise a stationary point 4.00 secured to frame member 221 and a scale .401 arranged on the hand wheel an of the adjusting device 290.

The workpiece may be held against the back supports 258 by a composite retaining device which-includes two fixtures 243, oneon the frame member 218 and the other on the frame member 221. The fixture which is mounted on the frame member 221 is illustrated in FIG. 8. It comprises a cylinder 244 for a piston whose rod 248 is connected to a rear platen 251 carrying a pair of tie rods 252, 254 whose front ends are secured to a front platen 255. The tie rods 252, 254 extend through suitable openings in the web of the frame member 221, and this web also supports the cylinder 244. When the operator admits a pressure fluid through the conduit 264 and allows spent fluid to escape through the conduit 262, the platen 256 is caused to move toward the front side of the workpiece 266 and compels the rear side of the workpiece to bear with requisite force against the respective back support 258. The construction of the otther fixture 243 which is carried by the frame member 218 is identical.

In order to properly adjust the workpiece 26.6 longitudinally of the strip 32%, the apparatus of FIGS. 7 and8 comprises a pair of end stops in the formvof levers 334 which are mounted on the two outermost blocks .264) in the same way as described in connection with levers 134. A third block 2643 is secured to the lower endportion of the frame member 221. This block is used when the length of the workpiece is less than the distance between the frame members 2-18, 220. Thus, and as shown in FIG. 7, the workpiece266 rests on the block260 of the frame member 218 and on the block 2600f theframe member 221. a

FIG. 9 illustrates the position of the drilling unit 31F4- when the tool 326 is utilizedto form dowel-holes in the left-hand end face of the workpiece 266. In order to move the unit 3 34- to the position of FIG. 9, the operator must release tie boss-353a by moving the pin-267 downwardly, as viewed in FIG. 8, and the operator must also withdraw the stud 322 so that the carriage.255 of the tool holder 222 may travel toward the left-handend of the frame. When the carriage reaches its leftmost position, the operator causes the entire tool holder 353, 353m, 259, 245', 247, 27?, 2% to turn through 90 degrees or store about the common vertical axis of the pin 283 and pivot 353 so that the tool 326 moves to apOSitiOn in which it is perpendicular to or in which it makesan angle of more or less than 90 degrees with the left-handend, face of the workpiece. If desired, the tool holder may be arrested in an intermediate angular position in which the axis of the tool 326 makes an acute angle with the front side or with the end face of the workpiece. As shown in FIG. 9, the boss 353a is formed with a series of openings 26'? .so that the pin 267 may arrest the tool holder in a number of angular positions.

The apparatus of FIGS. 7 to 9 also comprises means for controlling the depth of bores which are formed by the tool 326 in the end faces of a workpiece. Such depth control means comprises a rearwardly extending bracket 226 which is fixed to the connecting member 279 and which carries two precision adjustment screws 334) (see particularly FIG. 9) adapted to abut against-a stop 228 provided at the upper end of the movable frame member 221 or against a similar stop 228 which is provided at the upper end of the fixed frame member 218. Of course, the stops 228 may be complemented by a horizontal rail which may extend all the way between the frame members 218, 220 so that the depth of dowel-holes may be controlled in all positions of the tool support 222, i.e., also at the time the holes are being drilled into the front side of the workpiece. However, such modification is often unnecessary since the depth of holes in its front side may be controlled by proper positioning of the workpiece 266, i.e., by operating the adjusting devices 290. The stops 228 are of great advantage when the tool 326 is used to form holes in the end faces of the workpiece because one thereof then abuts against the one and/ or the other screw 330 and assists the tool holder to remain in a selected position. As a rule, it is not necessary to provide any arresting devices to fix the tool holder at the time the drilling unit 304 assumes the position of FIG. 9 because the pin 267 normally sutfices to prevent rotation of the tool holder. However, if it is desired to adjust the position of the tool holder in the plane of the workpiece 266, the pin 267 remains disconnected from the boss 353a so that the carriage 255 of the tool support may slide along the rail 278 in order to move the tool holder and the unit 304 toward or away from the adjacent end face of the workpiece. The screws 330 arrest such movement of the tool holder and simultaneously insure that the tool 326 may penetrate to a desired depth. Thus, it is possible to drill deeper dowel-holes into the end face than into the front side of the workpiece or vice versa. The greater the distance between the tool holder and the end face of a workpiece, the smaller will be the depth of the holes.

The setting means for the horizontal strip 320 includes an adjusting element 338 and screws 349 in the blocks 260. The manner in which such setting means may be manipulated to insure that the apparatus may be used for drilling patterns of mirror symmetrical holes in two separate workpieces is the same as described in connection with FIGS. and 6.

It goes without saying that the tool support 22 or 222 may carry two or more drilling or milling units so that the apparatus of my invention may be used for simultaneous drilling of two or' more holes. Also, the drilling unit 104 or 304 may be detached from its support so that it may be more readily cleaned, repaired or replaced, if necessary.

As a rule, the depth of a dowel-hole drilled into the end face of a workpiece exceeds the depth of dowel-holes which are drilled into the front side of the 'workpiece. This is due to the fact that a dowel received in the hole drilled into the end face of a flat panel is much more likely to break the adjacent portions of the panel than a dowel which is driven into a hole that is formed in a major surface (i.e., in the front side or rear side) of a panel.

In conventional apparatus, the tool and/ or the workpiece must be readjusted with considerable loss in time whenever it becomes necessary to change the depth of dowel-holes, particularly when comparatively deep holes mustbe drilled into the end face of a panel. The system of depth controlling means 226, 228, 335) renders it possible to adjust the depth of holes in the end faces of a workpiecewith very little delay. Similar time-saving adjustments may be made with the help of adjusting devices 290 when the operator desires to change the depth of dowel-holes which are drilled into the front side of the workpiece 266. Moreover, the devices 290 may be of help in adjusting the' workpiece in such a Way that the tool 326 will be located exactly midway between the front side and the rear side, i.e., that the dowel-holes drilled into the left-hand end face 2661) of the workpiece 266 will be located at the same distance from the front side 2660 and from the rear side 266d (see FIG. 9).

The tool holder is rotated in an anticlockwise direction when the-operator desires to drill holes in the right-hand lateral end face of the workpiece (reference being had id to FIG. 7) and when the carriage 255 reaches the frame member 221. On the other hand, while moving to the position of FIG. 9, the tool holder must rotate in a clockwise direction so as to move the tool 326 against the end face 2661: after the carriage reaches the frame member 218.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic and specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended Within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters ?atent is:

1. An apparatus for drilling holes and bores in panels and similar workpieces, comprising a work supporting frame including a first elongated frame member, a second elongated frame member fixed to one end of and extending substantially perpendicularly from said first frame member, and a third frame member substantially parallel with said second frame member and reciprocably mounted on said first frame member so as to be movable toward and away from said second frame member, said frame members defining between themselves a drilling area one dimension of which may be varied in response to movements of said third frame member; a retaining device comprising parts mounted on at least some of said frame members and arranged to fixed a workpiece to said frame; a tool support comprising a carriage mounted on and reciprocable in the longitudinal direction of said first frame member, said tool support further comprising an elongated tool holder substantially parallel with said second frame member and arranged to span the other dimension of said area; and a drilling unit mounted on and reciprocable in the longitudinal direction of said tool holder so that a tool mounted in said unit may be moved to selected sections of said area in response to movement of said unit with respect to or together with said holder. v

2. An apparatus as set forth in claim 1, further comprising first arresting means including cooperating component parts mounted on said first frame member and on said carriage for releasably locking said carriage in selected positions of adjustment with reference to said first frame member, and second arresting means including cooperating component parts mounted on said tool holder and on said drilling unit for releasably locking said unit in selected positions of adjustment with reference to said tool holder.

3. An apparatus as set forth in claim 2, wherein one component part of said first arresting means comprises an elongated rail detachably secured to said first frame member and a plurality of locating means longitudinally movably supported by said rail, another component part of said first arresting means comprising a locking member movably secured to said carriage and shiftable therewith into locking engagement with a selected one of said locating means, said rail being invertible with reference to said first frame member so that said locating means may be moved between two positions which are mirror symmetrical with reference to each other.

4. An apparatus as set forth in claim 1, further comprising an elongated rail provided on said tool holder and comprising a plurality of locating means longitudinal ly movably secured to said rail, and a locking member movably secured to said drilling unit, said locking memher being movable with said unit to engage a selected one of said locating means and to thereby arrest said unit in a selected position with reference to said tool holder.

5. An apparatus as set forth in claim 4, wherein said rail is detachable from and invertible with reference to said tool holder so that the locating means thereon may 3 5 be moved between two positions which are mirror symmetrical with reference to each other.

6. An apparatus as set forth in claim 1, further comprising arresting means including cooperating component parts mounted on said first frame member and on said carriage for releasably locking the carriage in selected positions of adjustment with reference to said first frame member.

7. An apparatus as set forth in claim 6, wherein one component part of said arresting means is an elongated rail and further comprising means for detachably securing said rail to said first frame member.

8. An apparatus as set forth in claim 7, further comprising setting means for said rail including an adjusting element secured to said rail and block means fixed to said frame, said adjusting element abutting against said block means to locate said rail against longitudinal displacement with reference to said frame.

9. An apparatus as set forth in claim 8, wherein said adjusting element is secured to one end of and extends at an angle from said rail.

16. An apparatus as set forth in claim 6, wherein one of said component parts includes an elongated rail provided on said first frame member and another of said component parts includes a locking member movably secured to said carriage, said locking member being arranged to engage said rail in selected positions of adjustment of said carriage with reference to said first frame member.

11. An apparatus as set forth in claim It wherein said rail is provided with longitudinally spaced recesses and said locking member comprises a projection which is receivable in a selected recess of said rail.

12. An apparatus as set forth in claim 10, wherein said rail comprises spaced projections and wherein said locking member is provided with a recess arranged to receive a selected projection of said rail.

13. An apparatus as set forth in claim 12, wherein said projections compriseconical portions.

14. An apparatus as set forth in claim 10, wherein said rail comprises a plurality of locating means which are adjustable in the longitudinal direction thereof and wherein said locking member is movable into engagement with a selected one of said locating means.

15. An apparatus as set forth in claim 14, wherein said rail is detachable from and invertible with reference to said first frame member so that the locating means thereon may be moved between two positions which are mirror symmetrical with reference to each other.

16. An apparatus as set forth in claim 14-, further comprising means for releasably locking said locating means to said rail.

17. An apparatus as set forth in claim 16, wherein said rail is provided with longitudinally extending guide means and wherein said locating means are movable along said guide'means.

18. An apparatus for drilling holes and bores in panels and similar workpieces, comprising a work supporting frame including a first elongated frame member, a second elongated frame member fixed to one end of and extending substantially perpendicularly from said first frame member, and a third frame member substantially parallel with said second frame member and reciprocably mounted on said first frame member so as to be movable toward and away from said second frame member, said frame members defining between themselves a drilling area one dimension of which may be varied in response to movements of said third frame member; a retaining device comprising a first fixture mounted on said second frame member and a second fixture mounted on said third frame member, said fixtures being arranged to fix a workpiece to said frame; a tool support comprising a carriage mounted on and reciprocable in the longitudinal direction of said first frame member, said tool support further comprising an elongated tool holder substantially parallel with said second frame member and arranged to span the other dimension of said area; and a drilling unit mounted on and reciprocable in the longitudinal direction of said tool holder so that a tool mounted in said unit may be moved to selected sections of said area in response to movement of said unit with respect to or together with said holder.

19. An apparatus as set forth in claim 18, wherein each of said fixtures comprises a platen which is reciprocable in directions perpendicular to the plane of saiddrilling area and which is arranged to engage the front side of a panel-shaped workpiece.

26. An apparatus as set forth in claim 19, wherein each of said fixtures further comprises a cylinder and piston assembly operatively connected with and arranged to reciprocate the respective platen.

21. An apparatus as set forth in claim 19, further comprising a first back support arranged to be placed between said second frame member and the rear side of a panelshaped workpiece and a second back support arranged to be placed between said third frame member and the rear side of the workpiece.

22. An apparatus as set forth in claim 21, further comprising adjusting devices arranged to change the distance between said back supports and the respective frame members.

23. An apparatus for drilling bores and holes in panels and similar workpieces of the type having a front side and a lateral end face which is substantially perpendicular to said front side, said apparatus comprising a work supporting frame including an elongated first frame member and additional frame members defining with said first frame member a drilling area one dimension of which is parallel with the longitudinal extension of said first frame member; a retaining device comprising parts arranged to fix a workpiece in said frame so that the major part of the front side and at least one lateral end face of the workpiece remains exposed and that such end face is substantially perpendicular to the longitudinal extension of said one frame member; a tool support comprising a carriage mounted on said frame and arranged to reciprocate along said first frame member adjacent to the front side of the workpiece, said tool support further comprising a tool holder which spans the other dimension of said drilling area and which is rotatable with respect to said carriage about an axis parallel with the end face of the workpiece so that, upon movement of the carriage into the proximity of such end face, the tool holder may be turned through at least degrees with reference to said carriage; locking means comprising elements provided on said carriage and on said holder for releasably fixing the holder in selected positions of angular adjustment; and a tool supporting unit provided on and shiftable along said tool holder so that a tool carried by said unit may be moved to selected sections. of said area to engage the front side or the end face of the workpiece in response to movementof said unit with or with respect to said tool holder and said support.

24-. An apparatus for drilling bores and holes in panels and similar workpieces of the type having a front side and a lateral end face which is substantially perpendicular to said front side, said apparatus comprising a Work supporting frarne including an elongated first frame member and additional frame members defining with said first frame member a drilling area one dimension of which is parallel with the longitudinal extension of said first frame member; a retaining device compn'sing parts arranged to fix a workpiece in said frame so that the major part of the front side and at least one lateral end face of the workpiece remains exposed and that such end face is. substantially perpendicular to the longitudinal extension of said one frame member; a tool support comprising a carriage mounted on said frame and arranged to reciprocate along said first frame member adjacent to the frOntside-of the workpiece, saidtool support further comprising a tool holder which spans the other dimension of said drilling area and which is rotatable with respect to said carriage about an axis parallel with the end face of the workpiece so that, upon movement of the carriage into the proximity of such end face, the tool holder may be turned through at least 90 degrees with reference to said carriage; locking means comprising elements provided on said carriage and on said holder for releasably fixing the holder in selected positions of angular adjustment; a tool supporting unit provided on and shiftable along said tool holder so that a tool carried by said unit may be moved to selected sections of said area to engage the front side or the end face of the workpiece in response to movement of said unit with or with respect to said tool holder and said support; and depth control means provided on said frame and on said tool holder for determining the depth of holes drilled into the end face of the workpiece when the tool holder is turned with respect to said carriage.

25. An apparatus as set forth in claim 24, wherein said depth control means comprises a stop element provided on said frame, a bracket element provided on said tool holder, and precision adjustment means provided on one of said elements and arranged to abut the other element when the tool holder is turned with respect to said carriage.

26. An apparatus as set forth in claim 24, wherein said additional frame members include two spaced frame members fixed to said first frame member and each adjacent to one lateral end face of the workpiece, said tool holder being rotatable in a clockwise direction when the carriage is adjacent to one of said two spaced frame members and in an anticlockwise direction when the carriage is adjacent to the other of said two frame members.

27. An apparatus as set forth in claim 26, wherein said depth control means comprises cooperating elements provided on said tool holder and on each of said two frame members for determining the depth of holes drilled in the end faces of the workpiece.

References Cited by the Examiner UNITED STATES PATENTS 480,040 8/1892 Saylor 776 1,310,034 7/1919 Powers 775 2,374,874 5/1945 McKee 775 2,479,293 8/1949 Bayless '775 2,623,419 12/1952 Wales 77-5 2,669,135 2/1954 Moore 77--5 3,052,150 9/1962 Ionker 77--5 3,116,652 1/1964 Bregnard 7764 WILLIAM W. DYER, JR., Primary Examiner.

FRANCIS S. I-IUSAR, Examiner. 

1. AN APPARATUS FOR DRILLING HOLES AND BORES IN PANELS AND SIMILAR WORKPIECES, COMPRISING A WORK SUPPORTING FRAME INCLUDING A FIRST ELONGATED FRAME MEMBER, A SECOND ELONGATED FRAME MEMBER FIXED TO ONE END OF AND EXTENDING SUBSTANTIALLY PERPENDICULARLY FROM SAID FIRST FRAME MEMBER, AND A THIRD FRAME MEMBER SUBSTANTIALLY PARALLEL WITH SAID SECOND FRAME MEMBER AND RECIPROCABLY MOUNTED ON SAID FIRST FRAME MEMBER SO AS TO BE MOVABLE TOWARD AND AWAY FROM SAID SECOND FRAME MEMBER, SAID FRAME MEMBERS DEFINING BETWEEN THEMSELVES A DRILLING AREA ONE DIMENSION OF WHICH MAY BE VARIED IN RESPONSE TO MOVEMENTS OF SAID THIRD FRAME MEMBER; A RETAINING DEVICE COMPRISING PARTS MOUNTED ON AT LEAST SOME OF SAID 